Washing and conditioning material for citrus fruit



Patented Mar. 14, 1939 WASHING AND CONDITIONING MATERIAL I FOR CITRUS-FRUIT 1 John RrMacRill, Whittier, and Robert D. Nedvidek, Pomona, Calif. ,.as'signors to California" Fruit Growers Exchange, Los Angeles, jCaliL," a corporation ofCalifornia No Drawing. Continuation of application Serial No. 705,026,, January 2, 1934', which is a division oi Serial No.,440,156,'Marcl 1 29, 1930. This application November 19, 1937, Serial No.

Those conversant with the art of processing citrus fruit are well aware of the number of diflicult problems which must be met and disposed of before oranges and other citrus fruit 5 are successfully and economically brought" from the groves and placed in the hands of the ultimate consumer. The major problem inthis art is that of cleaning and conditioning the fruit in such a way that it-may reach the market in the 1 most satisfactory and successful condition.- This problem includes the treatment of the fruit so as to prevent the development of molds thereon p v vention will become apparent to those skilled in and the elimination of insect life on the fruit.

Fruit fresh from the grove is never clean; Citrus groves are always carefully cultivated; which gives rise to quantities of dust and dirt, which in turn collect on the fruit. Furthermore, citrus groves are generally sprayed for the control of various insects, fungi and the like, and the spraysalways leave residues on theiruit.

Furthermore, .mealy bug deposits, black scal deposits, other insect deposits of various kinds and black smut are all found in varying amounts on the fruit. From time to time,'-whenever it is necessary to warm the groves by the procedure known as smudging, a considerable deposit of soot or smudge necessarily common the surface of the fruit. Obviously, anyandall' offthe foregoing materials, as well as any other similar foreign matter, must be completely removed from the fruit and the surface given a-rather glossy polish, before it is readyifor marketing. Polishing the fruit enhances its appearance and therefore its sales value. Y Y

In addition to the above, fruit coming from the groves to the packing housesis frequently found 5 to be infested with the beanthrips or Helio thrips .1, fasciatus' as well asfgther forms of insect'life. The fruit may, moreove'nbe infected with the well' known blue moldorother .molds, and limitsnatural state the fruit-is highly susceptible'to mold infection, which may occur during and by the packing house handlingalon'e.

It is apparent thatgbefore fruit maybe placed 5 on the market, it must likewise be free from any insect infestation and should preferably be rendered immune to -the attack -of the blue mold and/or other molds as well.

il'he present application is a continuation of 0 co-pending application Serial No; 705,026, filed- January 2, 1934, which was a division of and copendingjwithapplication, Serial No. 440,156 filed March 29, 1930, issued June 15, 1937 as Patent No. 2,084,062, in which a simple and effective 5 process of cleansing and conditioning fruits is 101m (me- 6;, v v I g .disclosed; That process simultaneously cleans ing treatment-of citrus fruit. Y

and conditions fruit, theapplication of waxy material at the same time being optional.

An object of this invention is to disclose an provide a combined washing and conditioning solution for use in the treatment of citrusfruit. Another "object is to disclose'andprovide a solutioncontaining ahydrocarbon dispersed therein, such solution'bein'g particularly adapted for the'simultaneous cleaning and moldinhibit- Still other objects and advantages of our inthe art from a contemplation of. the" invention as set forth' hereinafter.

Although theprior-art has disclosed methods by'means of which citrus fruits-"could be treated so as to inhibit'the development .of molds, the

prior art has not disclosed a method by 'means of" which the fruit could be ,freed from insect pests, such as the bean thripsjg, The bean thrips, Heliothrips fasciatus, referred to above, is most particularly diflicult to eradicate, due 'to its habit of secreting'itself under the button'ofthe fruit and "in the navel of the navel orange. There,

' minute air pockets are formed which enable the insect to be protected from the influence of any liquid with which the fruit as awholemay be placed-in contact. These minute air pockets are completely cleansed, and thus any insect infestation is completely eradicated.

Furthermore, although ordinary soap solutions have been employed in the cleansing of citrusfruits for a great many years, such prior cleansing solutions have not been capable of effectively removing all of the various forms of foreign matter with which the fruit is commonly covered. In other words, although ordinary dust and dirt could be removed by such prior cleansing solutions,the oily smudgeor smut and insect deposits could not be. completely removed without the use of other specially prepared solvents, which in turn did not successfully remove dirt or smudge.

Furthermore, strong cleansing solutions and ,sol-

Jvents tend, to remove the naturally occurring waxes present in the skins of the fruit. such wax removal accelerating the wrinkling and shrinkage of the fruit.

Briefly, our invention comprises soaking and/or washing and/or treating the fruit in a specific and predetermined manner with certain materials or combinations of materials, all as set 'tent of natural waxes present in the skins of the fruit, thus preventing wrinkling or shrinkage. In order for those skilled in the art to practice the invention, more specific forms of the various materials and modes'of operation will be set forth below.

In practicing the invention, we may employ as a base a soap solution. Such soap solution preferably contains an emulsion. The emulsion may be either a kerosene emulsion, or an emulsion containing a mold-inhibiting agent, such as pine oil or citrus terpenes; or both may be employed together.

Pine oil is a light-colored liquid of lighter specific gravity than water, obtained by extraction with a petrol solvent from pine chips. Pine oil normally contains borneol, alpha terpinol and dipentene. It has been found that in the preparation of these emulsions it is highly desirable to employ a water-soluble soap, and preferably an oleic acid soap of high purity. It has been found that an ethanolamine soap, such as tri ethanolamine oleate, produces emulsions which disperse readily when added to the basic soap solution, and which are thoroughly dispersed in the soap solution, thus assuring the penetration of all crevices and apertures in the fruit with the treating solution. Such penetration is, as stated hereinabove, essential in order to eradi cate insect pests such as the bean thrips, inas-. much as such minute insects are normally found in such crevices. this type of soap may be added as a separate ingredient to the mixture of materials employed in forming the emulsion, or such soap may be formed by the addition of oleic acid and ethanolamine so as to form the soap during the formation of the emulsion.

Throughout the following specification, parts are to be understood as parts by volume unless otherwise specified. Percentage values are to be understood as per cent by weight unless otherwise indicated.

We understand that the following values are approximately correct for the weight of one gallon of each of the liquids given: 7

- Pounds Citrus terpenes 7.0 Cottonseed oil 7.7 Kerosene 6.7 Oleic acid 7.3 Pine oil 7.2 Stearic acid 7.1 Triethanolamine 9.3 Water 8.3

One type of emulsion which may be employed, and hereafter referred to as a type of kerosene emulsion, may be formed by mixing two parts of kerosene with one part of water and adding thereto about 1%, and preferably less than 2%, of an oleate soap of the character described hereinabove, on the total weight of kerosene and water.

It is to be understood that When an oleic acid soap is used, quantities as small as 4*of an ounce of soap per gallon of kerosene may be successfully employed. Prefmerably, the soap is dissolved in the :watenand i the kerosene then added with agitation, so as to get a good emulsion. More thorough agitation is needed when small quantities of soap are used.

The kerosene may contain paraffin wax, vegetable oil, mineral oil or liquid petrolatum, or mixtures of these ingredients. The paraffin and/or wax may be used in varying amounts, such as from 0.05 to 1 pound per gallon of kerosene or other hydrocarbon solvent of this type. This is equivalent to about 0.75% to 15% of wax by Weight of kerosene. When wax is used, it may be melted and poured into the kerosene or shaved or disintegrated and allowed to dissolve therein. When vegetable oil is employed, from about 0.1 to 1 quart of oil may be added per gallon of kerosene, which is equivalent to about 2.8 to 28% of oil by weight of kerosene; when mineral oil is used, it may be added in the proportion-of about 0.05 to 0.4 quarts per gallon of kerosene, which is equivalent to about 1.3 to 10.4% of oil by weight of kerosene.

It is to be understood that when two of more of the above substancesare combined in the kerosene, the maximum proportions given above should not all be used together, although greater than the minimum proportions given may be used in combination. The exact proportions can be readily adjusted according to the result desired, and when one of these ingredients is increased the others may ordinarily be reduced correspondingly.

As an example of the type of emulsion defined hereinabove, we may take pounds of kerosene containing 1 to 10% of a vegetable oil such as linseed oil or cottonseed oil; 6 pounds of tri ethanolamine oleate are thoroughly dissolved in the kerosene, and such kerosene then thoroughly mixed with water in the proportion of from 2 to about 3 parts ofkerosene to 1 part of Water.

As another specific example of an emulsion coming within the general class described hereinabove, we may take 4 parts of kerosene containing from 2 to 20 quarts of vegetable oil per 20 gallons of kerosene, and add to it about 6% by weight of oleic acid. Such kerosene may then be intimately mixed to 1 part of water to which has been added triethanolamine in the amount of about 2% by weight on the basis of the weight of thekerosene.

It is to be understood that pine oil emulsions may be used in conjunction with the kerosene emulsion in the bath. For example, the emulsion may be produced by employing 1 part kerosene, 1 part of pine oil and 1 part of water, the emulsifying agent in this case being about 1% of the total weight of a suitable soap, gelatin, or other emulsifying agent stable in alkaline solutions.

A pine oil emulsion may be prepared, for example, by intimately mixing 6 parts of pine oil with about 5% by weight of oleic acid and 2% by weight of triethanolamine, said triethanolamine being dissolved first in 4 parts of water.

A pine oil emulsion may be added to a soap solution in sufficient quantities so as to produce a final concentration of pine oil in the bath of from about 0.02% to 0.25%. Preferably, the final concentration of pine oil should be kept within the limits of about 0.06% to 0.15%. Sufficient soap should be used to form a good suds. More may be added asand if needed. The temperature of the bath is This may vary over the range to 20%, on'the basis of thewater of the soap solution, and will be regulated in accordance with the character of the fruit to be cleaned and conditioned; it being obvious that very dirty fruit requires more cleansing agent and vice versa. Thus, when c'omparatively clean fruit is being handled, comparatively small amounts of a kerosene emulsion comparatively rich in oily and/or waxy ingredients may be used. The final washing and treating bath should not contain more than about 15% of kerosene, and preferably not more than 10% of kerosene. Smaller quantities are often adequate.

It is to be understood that in each of the emulsions mentioned hereinabove, whether kerosene or pine oil emulsions, the ingredients such as paraffin and/or wax and/or vegetable oil and/or mineral oil or liquid petrolatum may be used. It is particularly desirable to employ a waxy material such as paraflin when pine oil is used inasmuch as the pine oil is dissolved in the wax or liquid petrolatum and forms an unsubstantial film on -the treated fruit, such film imparting a glossy appearance to the fruit and containing the pine oil in insignificant quantities, but quantities sufficient to retard the development of molds on the fruit. When other waxes are used, a wax such as beeswax or carnauba wax is preferred.

The emulsions of the character described hereinabove may be prepared and then added to a suitable soap solution in the washingtank.

In addition to or instead of treating the fruit with an emulsion or combination of emulsions as set forth above, we may treat the fruit with a slightly different type of kerosene emulsion. For example, we take about 95 gallons of water and dissolve in it about 7 pounds of a. good commercial soap powder. We find that a soap powder made from cottonseed foots and cocoanut oil, and which contains about 35% of soda ash is very satisfactory for the purpose of this invention. In fact, we have found that the use of soda ash in conjunction with emulsions of the type here disclosed is desirable as, forexample, in that soda ash increases the, stability of the resulting solution or emulsion. To this soap-powder-water mixture we add a kerosene emulsion consisting of about gallons of kerosene and 2 /2 gallons of 7 water in which ounces of oleic acid soap of high purity have been dissolved.

The final concentration of kerosene in the final emulsion consisting of the soap solution and the more concentrated kerosene emulsion, should preferably be maintained at about 5%, for the sake of economy, although the kerosene emulsion may be added to the soap solution in quantities sufilcient to increase the content of kerosene in the final treating solution or emulsion. The bath prepared in this manner is kept at a temperature of from about 110 to 120 F., and the citrus fruit submerged in it for a period of time of from about 4 to 10 minutes, and preferably about 5 minutes. Such treatment is especially eificacious in eradicating the-Heliothrips fasciatus' and simultaneously removing any and all dirt, deposits or other foreign matter from the fruit.

Although it was stated hereinabove that the fruit is to be submerged in the treating bath, it is to be understood that complete immersion may not be entirely necessary, it only being desirable that all portions 01' the fruit be thoroughlyfcontacted with thetreating solution. V

After the fruit have been immersed in the treating" bath, they may pass to brushing rolls" where the fruit is sprayed," preferably with the same solution asthat existing in the bath; Whenfresh water is employed for spraying purposes, it should ordinarily be confined to the'latte'r half of the brushing rolls.

After leaving "the brushing rolls, the fruit may.

or may not'g o into additional tanks'for further treatment. Such additional tank or tanks may contain a solution similar to that in the first tank, and/or other agents such as mold-retarding agents which it is desired to have come in contact with the fruit. Inasmuch as the fruits are now in a thoroughly cleansed condition, the effect of the mold-inhibiting or retarding agents on the fruit is enhanced when such agents are used in subsequent tanks. After such complete treatment the fruit is then disposed of in known ways, according to packing house methods.

In case of lemons going to storage, for example, the fruit need not be dried or brushed, whereas fruit being sent to packing and shipping operations is preferably dried and brushed. Dry lemons, that is, lemons coming out of storage, particularly when not originally treated in accordance with the method of this invention, may be advantageously subjected to the action of the cleansing and conditioning solution of this invention upon being removed from storage.

In general, therefore, this invention relates to a simultaneous cleaning and treatment of citrus fruits by meansaof an aqueous soap solution containing a kerosene emulsion and/or a pine oil emulsion, or a mixture of pine oil and kerosene in emulsified, condition, the oily ingredients such as pine oil or kerosene being in the internal or dispersed phase.

In this manner, the fruit is completely cleansed and at the same time thoroughly freed froni infection and insect infestation. Moreover, treatment of the fruit in accordance with this invention retards decay from green or blue mold as well as other forms of diseases, such as alternaria. If a pine oil emulsion is used, the pine oil apparently is absorbed in the waxy outer coatings ordinarily found on the fruit and thus retained on the fruit, in the form of an inhibiting agent. The emulsions of kerosene, etc., described herein, may be contacted with fruit after the fruit have been cleansed by some other method.

Fruit treated with this invention are substantially free from tangible evidence of the presence .of foreign matter. Inother words, the pine oil concentrations are of'such order that their odor is not perceptible. When waxes or heavy oils, such as vegetable oils or mineral oil, are employed in the emulsions, the quantities employed are not sufficient to form a film on the outer surfaces of the fruit which is perceptible to the touch, and the only indication of their presence is the glossy, polished appearance of the fruit. Furthermore, the use of kerosene emulsions of this type does not result in fruit which bear the odor of kerosene.

In addition, the invention contemplates the use of a soap such as triethanolamine oleate. It should be understood that wherever we have spoken of triethanolamine we have had reference to the commercial product which apparently contains about 70% to 75% triethanolamine, 20% to 25% diethanolamine and 0.02% to 5% of monoethanolamine. Any one of the pure sub- 'ing operation, comprising:- an aqueous soap solution to which there has been added an emulsion. of kerosene and waxy material and an ethanolamine soap, and from about 0.02% to 0.25% of a. material from the group consisting of pine oil and citrus terpenes, the treating solution containing less than about 10% of kerosene and from about 0.75% to 15% of waxy ma.- terial by weight of said kerosene.

JOHN R. MACRILL.

ROBERT D. NEDVIDEK. 

